PhysX SDK 2.8.4: Optimized CPU Cloth Simulation

NVIDIA PhysX 2.8.4 cloth CPU demo
NVIDIA PhysX 2.8.4: CPU PhysX cloth demo

In the release notes of the PhysX SDK, there is this line:


  • Optimized cloth simulation on PS3, XBOX 360, PC CPU

The new PhysX SDK 2.8.4 comes with an optimized CPU cloth simulation path and is compiled with SSE2 option. Optimized CPU cloth simulation ? According to the test I did, this is true. The cloth sample shipped with PhysX SDK shows clearly the gain in performance. I tested on my dev system with a GTX 460 (R260.63) + Quad Core X 9650 @ 3.2GHz:

– PhysX 2.8.4: 443 FPS
– PhysX 2.8.3: 112 FPS

NVIDIA PhysX 2.8.3 cloth CPU demo
NVIDIA PhysX 2.8.3: CPU PhysX cloth demo

We have a gain of 4X in performance which is really nice.

The guys at have similar results with the cloth demo.

Thanks to Zogrim for the info 😉


  • filip007

    It’s about time PhysX on CPU, Crysis don’t use Cuda and still runs just fine i guess.

  • fpollan

    One cuestion?
    Run´s this demo (hardware)on GPU no-ageia?. In 275?

    I have demo, but runs “software” no “hardware”.

    Excuse my english.

  • Psolord

    Is the performance gain due to the SSE2 or is there some multithreaded cpu support as well?

    Can you check your CPU usage JegX?

  • Humm… there’s something strange:

    – CPU Cloth demo v2.8.3: GPU usage around 15%
    – CPU Cloth demo v2.8.4: GPU usage around 50%

    At first sight, there’s no multithreading support.

  • Psolord

    The gpu usage could be because the framerate qudrupled. I mean the gpu has to render 4 times faster no?

    I guess the same thing would happen in your fluid mark with CPU test and ATI card. If you used multithreading the framerate would jump so the card should render faster and the gpu usage would increase as well.

  • @Psolord: you’re right man! Shame on me…

  • Psolord

    Nuh, don’t worry about it.

    So what’s the verdict really? Did the performance gain come from SSE2 alone or something else? Have you pinpointed it?

    A Geeks3D friend told me that you cannot have more than 20% with SSE2. I had read to that article of the X87 PhysX instructions, that you can have 100% more performance with SSE2. Now we see 400%. I am confused! 😛

  • Stefem

    Probably is not(completely) related to SSE, the release note says “Optimized cloth simulation on PS3, XBOX 360, PC CPU” and SSE is an instruction set only of x86 CPU.

  • Maggi

    Hopefully this leads to an update for Mafia 2, increasing the Cloth PhysX performance by a huge margin … :)